Comparative Studies on Proximate Composition and Phytochemical Screening of Mango, Key lime, African star apple and African pear Seeds as Possible Coagulant Aids for Water Treatment

Abstract

Many fruits including mango (Mangifera indica), key lime (Citrus aurantiifolia), African star apple (Chrysophyllum albidum) and African or bush pear (Dacryodes edulis) are nutritionally valuable as human food, however after consumption of the fruits, their seeds are discarded as wastes since they are of no commercial value and this results in disposal problems. Hence assessment of the constituents of such waste seeds will enable their application to be considered. In this study the proximate composition and phytochemical constituents of the seeds of Duncan mango (Mangifera indica), key lime (Citrus aurantiifolia), African star apple (Chrysophyllum albidum: C. acreanum) and African or bush pear (Dacryodes edulis: D.e.var.edulis) obtained from southern part of Nigeria have been investigated and compared for the four different seeds. The results obtained from the proximate analyses showed that the major constituent of the seeds are carbohydrates, proteins and fats. The key lime seed was found to contain more protein and fat compared to the other seeds while the African star apple seed was found to contain the least fat and more carbohydrate compared to the other seeds. The phytochemicals detected in all the seeds were tannins, glycoside, coumarins and phenols, however steroids were absent. Only African star apple seed contained saponins and alkaloids. The results further indicated that only the key lime seed was devoid of flavonoid and starch. Tannins in plants have been reported to be among the active agents that bring about coagulation and natural polymers (proteins, carbohydrate (starch) etc.) act as bridging flocculants. Saponins, flavonoids coumarins and phenols have also been reported to posses antibacterial potentials against pathogenic organisms. This study shows that these seeds contain these constituents and they are present in reasonable amount. Therefore it is concluded that these seeds can be investigated as possible coagulant aids for drinking water treatment.